Boehmite-coated aluminum textile pirn

ABSTRACT

A TUBULAR ALUMINUM TEXTILE PIRN HAVING AN ALPHAALUMINA HYDRATE COATING THEREON.

United States Patent Offi ce 3,577,288 Patented May 4, 1971 3 577,288 BOEHMITE-COATED ALUMINUM TEXTILE PIRN Walter G. Zelley and Charles J. Walton, Lower Burrell,

Pa., assignors to Aluminum Company of America, Pittsburgh, Pa. No Drawing. Filed Nov. 25, 1968, Ser. No. 778,744 Int. Cl. C23f 7/06; B65h 75/18 US. Cl. 1486.27 11 Claims ABSTRACT OF THE DISCLOSURE A tubular aluminum textile pirn having an alphaalumina hydrate coating thereon.

BACKGROUND OF THE INVENTION This invention relates to textile pirns. More particularly, it relates to coated tubular aluminum textile pirns and a method of producing such pirns. As used herein, the term aluminum is defined as high purity aluminum, commercial grades thereof, and alloys of aluminum containing at least 80 percent by weight of elemental aluminum.

Textile pirns manufactured from various metals have been disclosed in the art heretofore. However, the several properties important in pirns utilized with the high strength synthetic filaments encountered in the present-day market place have not as yet been obtained through the use of an aluminum pirn. These properties include a high crush resistance when thread, such as raw nylon, is wound under tension; a capacity to retain in place without snagging the last layer of thread to be unwound; the prevention of smudging or discoloration on that last layer; and resistance against corrosion during storage prior to winding. These properties must be uniformly achieved in commercial textile pirns because several hundred pirns are usually connected in series in a commercial textile manufacturing operation. Therefore, if the thread on one pirn snags and tears, the entire line must be shut down. Similarly, if one pirn causes a smutting of the last layer of yarn, the discoloration is transmitted to the entire batch of yarn being processed, and substantial loss of valuable yarn results.

Conventional textile pirns are made of steel tubes having insertable plastic sleeves. Such plastic sleeves have surfaces that duplicate layers of WOlll'ld thread. These pirns, however, are extremely costly. Also, it is the practice in the textile industry to return the used pirns to the pirn manufacturer for inspection and repair. This is another significant disadvantage of steel tube-plastic insert pirns. As a result of these and other disadvantages, there has been a long-felt demand in the textile industry for a low-cost, single-use, disposable textile pirn which possesses all the above-mentioned desirable properties.

Accordingly, it is an object of this invention to provide a new and improved textile pirn, particularly an aluminum textile pirn. It is a further object of the invention to provide a new and improved low-cost, single-use, disposable aluminum textile pirn. Yet another object of the invention is to provide a new and improved aluminum textile pirn having high crush resistance, high humidity resistance and a non-snagging, non-smutting, thread-retaining, corrosion-resistant surface. A still further object of the invention is to provide a new and improved method for producing an aluminum textile pair. Other objects and advantages of the invention will be apparent to those skilled in the art from the description and claims which follow.

SUMMARY OF THE INVENTION In its broader aspects the invention concerns a textile pirn comprising a tubular body of aluminum having an alpha-alumina hydrate coating thereon. The preferred thickness of the coating is at least about 0.4 mg./in. of surface. To aid in achieving the thread-retaining surface referred to hereinabove, the surface beneath the hydrate coatlng is preferably roughened to prevent sagging of the first layer of yarn thereon. The preferred degree of roughness is from about 30 to about 70 microinches RMS (root mean square) as measured by a profilometer. It may be achieved, for example, by dry grinding the surface of the tubular body with a three-station grinder, using a Wheel sequence, for example, of -240-320 grit. Another way to obtain the desired amount of roughness is by wet grinding, for example, by grinding the tubular body of aluminum with emery belts of 180-240-240 grit sequence using a lubricant such as kerosene.

The alpha-alumina monohydrate, commonly referred to as boehmite, coating may be obtained using a procedure such as described in US. Patent 3,266,900, for example, by treatment with hot water, preferably distilled or deionized water, at an alkaline pH, preferably from about 8.5 to about 10.5, and at a preferred temperature of between about F. and the boiling point. The water preferably contains a small amount of triethanolamine, for example, from about 0.5 to 5 ml./l., preferably about 0.5-1.5 mL/l. Treatment time is preferably from about 5 seconds to 15 minutes.

The base tubular body of aluminum may be formed by induction welding of coiled aluminum sheet. The pirn body may be of any desired length, e.g., 13 inches. The inner diameter of the tube may be about 1.875 inches. For example, for high crush resistance when the pirn is wound with thread under tension, the wall of the tube is preferably at least .045-inch thick. The pirn of the invention preferably has a minimum yield strength of 43,000 p.s.i. The tube weld flash may be removed from both inside and outside the tubular body according to conventional practice. The ends of the tubular pirn are preferably deburred and chamfered on the outside surfaces of both ends, for example, to a radius of 0.020 inch. Deburring and chamfering permits the handling of the pirn without fear of injury.

The invention also generally concerns a method for producing a coated tubular aluminum textile pirn by forming an alpha-alumina monohydrate (boehmite) coating thereon. According to a preferred embodiment, the surface is first roughened, preferably to the degree set out above, and the surface then cleaned prior to forming the alpha alumina monohydrate coating thereon. The surface may next be rinsed and dried.

The cleaning of the rough surface may be accomplished by various known cleaning systems such as solvent cleaning, non-etching chemical cleaning, or mild-etch cleaning, provided the etch loss is limited to avoid loss of the desired amount of roughness of the finished surface. Regardless of the particular cleaning system employed, the surface obtained prior to formation of the alpha alumina monohydrate coating should be sufiiciently clean to prevent any adverse effect upon the rough finish. Especially good results have been obtained with an aqueous nonetching solution maintained at a temperature of about F. containing sodium carbonate, trisodium phosphate, sodium metasilicate, and a surfactant, e.g., Nacconol 40F, or an organic isocyanate such as toluene diisocyanate. The pirn is preferably conveniently immersed in the cleaning solution for at least 1 minute and then rinsed with water.

The pirn is now ready for formation thereon of the boehmite coating, which may be applied by immersing the clean rough pirn in a hot aqueous solution as described hereinabove. Following treatment with the alpha alumina monohydrate solution, the pirn is preferablyrinsed with Water and then dried, making it ready for yarn to be wound thereon.

The following example is illustrative of the invention.

Several 13-inch tubes were produced by induction welding coiled sheet of an aluminum alloy designated by The Aluminum Association as and commonly known as 5086-H39. The sheet had a thickness of about .0465 inch. This alloy has a nominal composition of 4.0 percent magnesium, 0.45 percent manganese, 0.10 percent chromium, balance aluminum, plus other incidental impurities normally associated with aluminum alloys. The tube weld flash was removed from each tube. The outside surfaces of the tubes received a rough surface by being dry ground on a three-stage centerless grinding machine (having segmented flap cloth wheels) using a sequence of 150, 240, and 320 grit wheels. After grinding, the outside surfaces of both ends of the tubes were deburred and chamfered to a radius of 0.20 inch. The tubes were next immersed for three minutes in a non-etching cleaning solution maintained at a temperature of 180 R, which solution contained 3 ounces per gallon of sodium carbonate, 3 ounces per gallon of trisodium phosphate, 2 ounces per gallon of sodium metasilicate, and /3 ounce per gallon of Nacconol 40F surfactant. The roughness of the surface was approximately 50 microinches RMS according to the aforementioned profilometer test. The tubes were then activated by treating in a sodium hydroxide solution atroom temperature (here about 70 F.) for 30 seconds. The etch loss in the NaOH solution did not exceed 35 mg./ft. and was not detrimental to the rough surface. The, tubes were next thoroughly rinsed with water and immersed for 3 minutes in an aqueous solution (deionized water) containing v1 ml./l. triethanolamine and maintained at the boiling temperature (about 212 F.) and'a pH of 9.5. Following removal from the aqueous solution, after obtaining a coating of 0.5 mg./in. the tubes were thoroughly rinsed with Water and air dried. The finished pirns had a yield strength of not less than 43,000 pounds per square inch.

Approximately three pounds of raw nylon were wound on each pirn, and the pirns were placed in series on weaving apparatus. The yarn spun off of each pirn was not soiled, and no snags or tears occurred in the unwinding operation.

While we have disclosed preferred embodiments of the invention for illustrative purposes, it is obvious that various modifications of the invention are possible within the spirit and scope of the following claims.

Having thus described our invention and certain preferred embodiments thereof, we claim:

1. A textile pirn having a surface of improved snag resistance, said pirn comprising a tubular body of aluminum coated with alpha-alumina monohydrate, said tubular body having a rough finished base for the alphaalumina monohydrate coating.

2. The textile pirn of claim 1 wherein the alphaalumina hydrate coated on the tubular body of aluminum amounts to at least about 0.4 milligram per square inch of surface.

3. The textile pirn of claim 1 wherein the minimum wall thickness of said tubular body is about .045 inch, the ends of said tubular body are chamfered, and said tubular body has a yield strength of at least about 43,000 pounds per square inch.

4. A method of producing a coated tubular aluminum textile pirn comprising roughening an aluminum tubular body and then forming an alpha-alumina monohydrate coating on the roughened pirn, thereby improving the snag resistance.

5. The method of claim 4 wherein the surface of the aluminum is roughened by wet or dry grinding.

6. The method of claim 4 wherein th alpha-alumina monohydrate coating is formed by treatment of the aluminum tubular body for from about 5 seconds to about 15 minutes with an aqueous solution having a pH of from about 8.5 to about 10.5 and a temperature of from about F. to about 215 F.

7. The method of claim 6 wherein the aqueous solution contains a small amount of triethanolamine.

8. The method of claim 6 wherein before the forming Df the alpha-alumina monohydrate coating on the surface of the aluminum tubular body the surface is first roughened, then chemically cleaned and then activated by treatment with a dilute solution of sodium hydroxide.

9. A method of producing a coated tubular aluminum textile pirn comprising:

(a) forming a rough surface on a tubular body of aluminum by wet or dry grinding;

(b) cleaning said rough surface of said tubular body of aluminum;

(c) forming an alpha-alumina monohydrate coating on said cleaned rough surface, said coating having weight of at least 0.4 milligram per square inch of aluminum surface; and

(d) rinsing said coated tubular body and drying the same, thereby making said pirn resistant to snagging.

10. The method of claim 9 wherein the alpha-alumina monohydrate coating is formed by immersing the tubular body of aluminum in an aqueous solution for from about 5 seconds to 15 minutes at a temperature of from about 175 F. to about 215 and at a pH of from about 8.5 to about 10.5.

11. The method of claim 9 wherein the aqueous solution contains triethanolamine.

References Cited UNITED STATES PATENTS 2,859,148 11/1958 Altenpohl l48-6.27 3,039,899 6/1962 Keller et a1. 1486.27X 3,266,900 8/1966 Zelley 9675 3,380,860 4/1968 Lipinski 148-6.27 3,403,872 10/1968 Williams et a1. 2421l8.31

RALPH S. KENDALL, Primary Examiner U.S. Cl. X.R. 

